The gradual transition between disc and cone maintains relatively stable impedance over a very wide frequency range.
Antennas · F1SYH
Discone antenna
The Discone combines an upper disc and lower cone. It is especially valued for wideband VHF/UHF reception.
VHF
UHF
Large bande
Operating principle
Main characteristics
Typical gain
Proche de 0 à 2 dBi
Impedance
Environ 50 Ω sur large plage
Polarization
Verticale
Difficulty
Intermédiaire
Dimensions and design
The lower frequency mainly depends on cone length. Upper frequency depends more on disc dimensions, spacing and construction accuracy.
Construction and tuning
Step 1
Define the desired lowest frequency.
Step 2
Calculate cone length and angle.
Step 3
Build the disc or upper radials.
Step 4
Maintain a small feed-point gap.
Step 5
Use low-loss coaxial cable.
Advantages
- Very wide bandwidth.
- Omnidirectional pattern.
- Excellent for scanners and SDR.
- No frequent mechanical tuning.
Limitations
- Modest gain.
- Large dimensions for low frequencies.
- Transmit performance varies by band.
- Requires accurate mechanical construction.
History and origin
The Discone was described and patented in the mid-1940s by Armig G. Kandoian for wideband communications.
Safety
Radial ends should be rounded or protected to prevent injury.